LIFE HISTORIES OF FAMILIAR PLANTS 



wild camomile are more evolved and belong to 

 a higher type of flower than the familiar butter- 

 cup, rose, or bramble, and now I will explain why. 



As time went on and the coloured petals suc- 

 ceeded so well in drawing the attention of in- 

 sects, it happened that the nectar and colours 

 of certain plants proved more attractive to certain 

 types of insects than to others ; so they gradually 

 adapted themselves to these particular insect 

 visitors. If you will notice the next stalk of fox- 

 glove flowers (Fig. 4, Plate 3) that you meet with, 

 it will make my point quite clear. These flowers, 

 it will be seen, have joined their petals together to 

 form a tube that fits almost exactly the humble- 

 bee that visits them. A foxglove, then, is a higher 

 type of flower than our bramble, buttercup, or 

 rose, because it has specialised by uniting its petals 

 together to form a tube specially adapted to a par- 

 ticular form of insect, an adaptation which makes it 

 practically certain of pollination when the bee 

 enters, whereas in open flowers, as buttercups and 

 wild roses, pollination is not so certain. 



Also, notice that the flowers of the foxglove 

 are arranged on a special central stalk (not mixed 

 up with leaves), and that they open from the 

 bottom upwards, the youngest being at the top 

 (Fig. 4, Plate 3). Of course, it is plain that the 

 bee can only visit one flower on the stalk at a 

 time ; but now let us suppose that a plant, with a 

 stalk of flowers something on the lines of the fox- 

 glove, should slowly shorten its stalk and evolve 

 such an arrangement of its flowers that they 



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